The leakage of liquids, and in particular stealthy leakage, can occur in apartments and houses, as well as in other real estate and cause serious damage, requiring expensive reparations. It is not unusual that minor leaks occur in or around valves in both old and modern hot water radiators when the liquid flow is adjusted, or when the radiator is aired that is the top valve is opened in order to remove entrapped air. Leakages in pipe joints, couplings and fittings for example to household appliances, such as dish washers and washing machines, may be difficult to detect, in particular when built in or hidden.
A leak can take the form of drops, droplets, or a fine spray or mist of liquids. A leak can also occur in the form of a liquid film, spreading along a pipe. Even the condensation of liquid on a cold water pipe can cause damage. It frequently happens that such minor leaks/condensation is not discovered until the secondary damage becomes apparent. At that stage, the extent of reparations necessary will also become greater and thus more expensive.
Various devices for the detection of leakage are known. U.S. Pat. No. 6,128,947 describes a gasket or apron having a colorant-emitting disc attached thereto, the colorant in said disc being released by contact with water. This disc is however intended to be permanently mounted under a toilet, and cannot be held to be easily installed or removed.
DE 4 105 044 describes a method for testing the leak-tightness of a pipe, either by holding the pipe at a slight vacuum or over-pressure and detecting changes in this vacuum or pressure, or by observing a pigment layer surrounding the pipe, which pigment reacts with an indicator substance emitted from said pipe.
U.S. Pat. No. 3,485,085 describes a method for detecting leaks in the cooling system of a power reactor, wherein an apertured container is placed around a point where leakage may occur, and a tape whose resistivity changes on exposure to moisture is placed over the aperture of said container, and changes in the resistivity determined.
GB 2307558 describes a thin covering to be applied to pipe lines conveying a liquid medium, such as for example fuel, wherein said covering consists of a material which reacts in a chemical-physical manner with the liquid, producing a colour change.
U.S. Pat. No. 2,601,840 describes a leakage indicating cover for pipe flanges and valves, wherein said cover has a fabric lining impregnated with a chemical which changes colour when contacted by an acid or base. Among the examples mentioned are thymol blue, methyl red, phenolphthalein and litmus.
WO 94/02772 describes a method for leak detection where a film of colour change material is formed on the outer surface of a liquid-carrying hose, where the material will react with possible escaping liquid to provide a visible indication. The colour change material is completely encapsulated in a protective film, and preferably applied to the hose by spraying.
JP 61250535 describes a tape for detecting leakage of water, wherein said tape is printed, coated or impregnated with a water-soluble colouring material, which becomes blotted upon contact with water.
Regardless of the considerable amount of prior art in this field, it appears that there still remains a need for a simple, inexpensive and easily applicable device, as well as a simple and reliable method for the detection of minute amounts of liquid or stealthy leakage. One objective of the present invention is to make available such a device, which is easily placed at the site of a suspected leak, easily removed and replaced. Another objective is to ensure that the device and method are reliable also when the leakage is abundant, i.e. that the indicator substance is not rinsed away or diluted to an extent that the colour indicating leakage becomes unrecognisable.
A further objective is that the device and method are not influenced by ambient humidity. Further objectives and the corresponding features of the invention, as well as the advantages thereof, will become apparent to a skilled person upon a closer study of the description and examples.